Known client mailing applications like LotUs™ NoteS™ or Microsoft™ Outlook™, up to now, do not provide a standard way of extracting and moving a single note or mail document out of and into a mail database file. This means that a whole mail database file must always be stored, just to append a single mail item. For this reason, Lotus Notes has already started implementing an XML solution. However, its format as well as its interface are still under evaluation (see http://www.notes.net/sandbox.nsf/ . . . ).
One drawback of the above described XML approach is that an XML data representation of mail or notes does not completely preserve all properties of such documents.
In addition to that, XML is a readable ASCII-based format. That means, if someone did not have access to an original note, but has the XML representation of a note, one can read the note's content e.g. by browsing it in a regular text editor. Further, converting documents to XML and back means a lot of overhead.
Therefore, a mechanism is needed to extract a document, as it is, in some compact format without being able to read the document, if it is protected.
Further, when the document is restored, it must be identical to the original one. That is, besides the content, it must also have the same properties.